32 



MAINE STATE COLLEGE 



It is believed that the percentages of starch given in this connec- 

 tion much more nearly represent the actual amounts present in the 

 fodders analyzed than when the ordinary method of analysis is 

 followed.* 



The method of starch determination generally used is to treat the 

 substance for a given period with hot dilute acid, which results in 

 the conversion not only of starch but partly, at least, of cellulose 

 and gums into glucose. The amount of this sugar is ascertained 

 by its action in precipitating copper oxide from Fehling's solution 

 and all the sugar thus found is assumed to come from starch alone, 

 which is far from the truth. If we did not have reason to believe 

 that starch is greatly superior in food value to the cellulose, gums, 

 etc., which suffer hydrolysis by the action of mineral acids, this 

 assumption would be less fatal to correct conclusions. But so long 

 as starch appears to be entirely digestible, while these other bodies 

 certainly are not, and so long as there is good reason for regarding 

 digested cellulose and gums as less efficient nutrients than digested 

 starch, it is certainly nothing less than absurd to go on assuming 

 that all the sugar produced when vegetable substances are treated 

 with mineral acids comes from starch. The method used here was 

 the conversion of the starch into water-soluble compounds through 

 the action of a ferment known as diastase In the ease of a few 

 samples the acid and diastase methods have been compared. 



TABLE XIV. 



GOMPAKISOK OF PBKCEHTAGE8 ' >F BTAKCH AS FOTTND BT THE ACID AVI) BT THE 

 DIASTASE METHODS. 



In 100 parts water-free 

 substance. 



: ■ ~ - X — x = 



— - a 

 ? jo S 



:. -• — 



CLX— Southern Corn, immature, no ears, Field I ' .22 



CLXI— Southern Corn, immature, no ears, Field II. . 48-96 



C'LXII— Maine Field Corn, mature, Field I 61.64 



CLXIII— Maine Field Com, mature, Field II 58-74 



CLXX— Southern Corn silage, from CLX 46-64 



CLXXVI— Southern Corn silage, from CLXI 42.84 



CLXXI— Maine Field Corn silage, from C'LXII 59.31 



CLXXIII— Maine Field Corn silage, from CLXIII . . . 57-91 



-Mr. Bartlett describes his methods on subsequent pages 



2.03 



2.24 



18.58 



12.66 



3-70 



3.56 



15.32 



17.43 



14.98 

 15.27 

 30.32 

 23-97 

 14.63 

 14.90 

 29.50 

 30.00 



12.95 

 13.03 



11.74 

 11.31 

 10.93 

 11.35 

 11.18 

 12.57 



of this report. 



